LC-ESI-MS Study of the Flavonoid Glycoside Malonates of Red Clover (Trifolium pratense)

Abstract

High-performance liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) was applied to the analysis of the flavonoids and their glycoside malonates of the flowers and leaves of red clover (Trifolium pratense). Through LC-MS comparative studies on the plant extracts and their malonate-free extracts, approximately 20 flavonoid glycoside malonates were detected in the flower extract. Eight were identified as genistin 6' '-O-malonate (39), formononetin 7-O-beta-D-glucoside 6' '-O-malonate (40), biochanin A 7-O-beta-D-glucoside 6' '-O-malonate (41), trifoside 6' '-O-malonate (42), irilone 4'-O-beta-D-glucoside 6' '-O-malonate (43), pratensein 7-O-beta-D-glucoside 6' '-O-malonate (44), isoquercitrin 6' '-O-malonate (45), and 3-methylquercetin 7-O-beta-D-glucoside 6' '-O-malonate (46). About 15 other flavonoids and clovamides were proved to be present in this extract. The study also found that the flowers contained flavones as the major flavonoids, whereas the leaves had isoflavones as the major flavonoids. This is the first detection of the six malonates (39 and 42-46) in the extracts of red clover, and among them, 42, 43, and 46 are new compounds.

The polyphenolic profiles of common bean (Phaseolus vulgaris L.)

“…Peak F-6 had the same UV spectra and aglycone ion as peak F-5 (quercetin 3-O-glucoside), but its molecular ion is 86 amu larger than that of F5 and or 248 amu larger than that of its aglycone. Thus, F-6 was tentatively identified as quercetin 3-O-(6″-malonyl) glucoside (Cuyckems & Cleays, 2004;Lin et al, 2000). Similarly, peaks F-9 and F-10 were identified as kaempferol 3-O-(6″-malonyl)glucoside and kaempferol 3-O-(malonyl)glucoside.…”

“…Based on the data presented in Table 2, the trace peaks A-4, A-8 and A-7 of small red beans were tentatively identified as pelargonodin 3,5-O,O-diglucoside, pelargonidin 3-O-(6″-malonyl)glucoside and cyandin 3-O-(6″ -malonyl) glucoside, respectively. The later two anthocyanins had molecular ions that were 248 amu larger than their aglycones and 86 amu larger than that of their glucosides; a typical pattern for flavonoid malonylglucosides (Cuyckems & Cleays, 2004;Lin et al, 2000).…”

“…Similarly, peaks F-9 and F-10 were identified as kaempferol 3-O-(6″-malonyl)glucoside and kaempferol 3-O-(malonyl)glucoside. F-9 was identified as kaempferol 3-O-(6″-malonyl)glucoside because linkage of the malonyl at the 6″-position of the sugar is far more common (Lin et al, 2000;Svelikova et al, 2004). The position of malonyl group on the sugar moiety was not determined for peak F-10.…”

Ultrasound‐assisted solid‐phase extraction coupled with photodiode‐array and fluorescence detection for chemotaxonomy of isoflavone phytoestrogens in Trifolium L. (Clover) species

“…For example, a two-dimensional SPE method, using Oasis HLB, RP 105 and Abselut sorbents in combination with an LC -ESI MS system, enabled the identification of fourteen isoflavone glycoside malonates in T. pratense [12]. Lin et al [13] used the same LC -ESI MS system and identified six isoflavone glucoside malonates in flowers and leaves of red clover. Extraction enhanced by sonication and followed by acid and basic hydrolysis was used by Delmonte and co-workers [14] to determine isoflavone levels in dietary supplements containing red clover.…”

Separation and analysis of phenylethanoid glycosides inLamiophlomis rotataby high-performance liquid chromatography

“…It has been reported that iridoid glycosides and flavonoids are two major components of L. rotata [3][4][5]. Many HPLC [6][7][8][9], CE [10][11][12][13][14], highperformance liquid chromatographic-mass spectrometric (HPLC-MS) [15][16][17], and gas chromatographic-mass spectrometric (GC-MS) [18,19] methods have been developed for the separation and analysis of iridoid glycosides and flavonoids. 8-O-acetylshanzhiside methylester, 6-O-acetylshanzhiside methylester, shanzhiside methylester, 8-deoxyshanzhiside, sesamoside, loganin, penstemoside, phlomiol, 7, 8-dehydropenstemoside, phloyoside I, phloyoside II, lamiophlomiside, phlorigidoside C, and seven other iridoid diglycosides have been isolated and reported as iridoid glycosides in the last 20 years [20][21][22][23].…”